METHOD OF REDUCING AMOUNT OF CALCULATION REQUIRED FOR PITCH SEARCH IN VOCODER

摘要

PURPOSE: A method of reducing the amount of calculation required for pitch search in a vocoder is provided to decrease the amount of calculation needed for pitch search by restricting a section that requires correlation calculation for pitch search. CONSTITUTION: When a voice signal is inputted(202), the voice signal is passes through an analysis filter and a synthesis filter(204,206). The voice signal that passed through the filters passes through a cubing filter(208). The cubing filter emphasizes a high-amplitude portion of the voice signal but suppresses a low-amplitude portion of the voice signal. The voice signal that passed through the cubing filter passes through a clipping filter that removes a portion of the voice signal lower than a threshold value(210). A high-amplitude region of the voice signal that passed through the clipping filter is determined(212), and pitch delay and pitch gain are obtained.